<article id="wikiArticle">
<div> <div class="blockIndicator obsolete obsoleteHeader"><p><strong><span class="icon-only-inline" title="This is an obsolete API and is no longer guaranteed to work."><i class="icon-trash"> </i></span> 已废弃</strong><br/>This feature is obsolete. Although it may still work in some browsers, its use is discouraged since it could be removed at any time. Try to avoid using it.</p></div></div>
<p><code><strong>clear()</strong></code>用来从 <code>WeakMap对象中移除所有元素。</code>但不再是ECMAScript和它的实现部分。</p>
<div class="warning">
<p>Warning:</p>
<p><img alt="WeakMap(no clear() any more).png" src="https://mdn.mozillademos.org/files/15608/WeakMap(no%20clear()%20any%20more).png" style="height: 490px; width: 735px;"/></p>
</div>
<h2 id="语法">语法</h2>
<pre><code class="language-javascript"><em>wm</em>.clear();</code></pre>
<h2 id="示例">示例</h2>
<h3 id="使用_clear_方法">使用 <code>clear</code> 方法</h3>
<pre><code class="language-js;highlight:[10] example-bad">var wm = new WeakMap();
var obj = {};

wm.set(obj, "foo");
wm.set(window, "bar");

wm.has(obj); // true
wm.has(window); // true

wm.clear();

wm.has(obj)  // false
wm.has(window)  // false
</code></pre>
<h2 id="规范">规范</h2>
<p>当前版本或者起草中没有这个方法，这个方法在版本 28（2014 年 10 月 14） 之前是 ECMAScript 6 起草规范的一部分，但是在起草之后的版本中被移除了。它不在是最终标准的一部分了 。</p>
<h2 id="浏览器兼容性">浏览器兼容性</h2>
<p></p><div class="blockIndicator warning"><strong><a class="external" href="https://github.com/mdn/browser-compat-data" rel="noopener">We're converting our compatibility data into a machine-readable JSON format</a></strong>.
            This compatibility table still uses the old format,
            because we haven't yet converted the data it contains.
            <strong><a class="new" href="/zh-CN/docs/MDN/Contribute/Structures/Compatibility_tables" rel="nofollow">Find out how you can help!</a></strong></div>
<div class="htab">
<a id="AutoCompatibilityTable" name="AutoCompatibilityTable"></a>
<ul>
<li class="selected"><a>Desktop</a></li>
<li><a>Mobile</a></li>
</ul>
</div><p></p>
<div id="compat-desktop">
<table class="compat-table">
<tbody>
<tr>
<th>Feature</th>
<th>Chrome</th>
<th>Firefox (Gecko)</th>
<th>Internet Explorer</th>
<th>Opera</th>
<th>Safari</th>
</tr>
<tr>
<td>Basic support</td>
<td>36</td>
<td><span style="color: #f00;">未实现</span> [1]</td>
<td>11</td>
<td>23</td>
<td>7.1</td>
</tr>
</tbody>
</table>
</div>
<div id="compat-mobile">
<table class="compat-table">
<tbody>
<tr>
<th>Feature</th>
<th>Android</th>
<th>Firefox Mobile (Gecko)</th>
<th>IE Mobile</th>
<th>Opera Mobile</th>
<th>Safari Mobile</th>
</tr>
<tr>
<td>Basic support</td>
<td><span style="color: #f00;">未实现</span></td>
<td><span style="color: #f00;">未实现</span> [1]</td>
<td><span style="color: #f00;">未实现</span></td>
<td><span style="color: #f00;">未实现</span></td>
<td>8</td>
</tr>
</tbody>
</table>
</div>
<p>[1] The <code>clear()</code> 曾经在高于 20 版本低于 45 版本之间被支持。</p>
<h2 id="相近">相近</h2>
<ul>
<li><a href="Reference/WeakMap" title="此页面仍未被本地化, 期待您的翻译!"><code>WeakMap</code></a></li>
</ul>
</article>